This invention relates to the art of optical apparatus for viewing an object and making a photographic record thereof utilizing a photoflash light source, and more particularly to a new and improved electrical circuit for operating and controlling such apparatus.
One area of use of the present invention is in an ophthalmic examining and photographic recording instrument otherwise known as an ophthalmoscope, although the principles of the invention can be variously applied. Optical apparatus of this type includes an illuminating light source and a photoflash light source, and the circuit for controlling the operation of the light sources should include sections which co-operate in an efficient and effective manner to provide an instrument which is versatile and easy to use. With respect to control of the photoflash light source, some important considerations are control of the voltage for operation of the photoflash and enabling the system optics to reach a steady state condition before the photoflash is operated. Also, since such photoflash light sources are operated by discharge of a capacitor in a charge storing and discharge circuit associated therewith, it is important that the circuits be designed to prevent electrical hazards associated with connection and disconnection of such light sources and associated circuits from the apparatus. In addition, it would be highly desirable to incorporate integrated circuit chip technology in such circuits.